Comparative Cost-utility Analysis Between Aprepitant- and Fosaprepitant-containing Regimens To Prevent Chemotherapy-induced Nausea and Vomiting in Patients Receiving Highly Emetogenic Chemotherapy in Japan.

PURPOSE: Clinical trials have shown that the addition of aprepitant (APR) or a phosphorylated prodrug of aprepitant, fosaprepitant (FosAPR) as prophylactic antiemetic therapy consisting of a 5-hydrotryptamine-3 receptor antagonist and dexamethasone is effective in patients receiving highly emetogenic chemotherapy. These combination therapies have been commonly used in Japan. In the present study, we performed a cost-utility analysis of APR and FosAPR in the context of the Japanese medical insurance system, and economic efficiency was compared.

METHODS: Data from randomized controlled trials that examined the efficacy of APR and FosAPR in the Japanese population were used. A decision tree was constructed to estimate the effectiveness of chemotherapy for 5 days from the day of the treatment and the cost associated with outpatient chemotherapy from the perspective of a payer. Health outcome was expressed in quality-adjusted life-years (QALYs), and costs were estimated based on medical fees and drug prices from 2018. An incremental cost-effectiveness ratio (ICER) was calculated for each regimen containing either APR or FosAPR. The robustness of the model was assessed using 1-way and probabilistic sensitivity analysis.

FINDINGS: The base-case analysis estimated that the addition of APR or FosAPR would have incremental effects of 0.00166 and 0.00143 QALY and incremental costs of 8305 and 11,348 JPY (74 and 101 USD [1 USD = 112.17 JPY]), resulting in ICERs of 4,992,172 and 7,955,560 JPY/QALY (44,505 and 70,924 USD/QALY), respectively. Sensitivity analysis revealed that the probability of a complete response for delayed chemotherapy-induced nausea and vomiting had the most influence on the ICERs. Reductions in the drug costs of APR and FosAPR also had an effect on the ICERs. According to the probabilistic sensitivity analysis, APR and FosAPR were dominant in terms of cost-effectiveness in 48.7% and 8.55% of cases, respectively.

IMPLICATIONS: The ICER of outpatient prophylactic antiemetic therapy in patients receiving highly emetogenic chemotherapy was calculated in the context of the Japanese medical insurance system. Assuming the willingness-to-pay of 5,000,000 JPY/QALY based on the calculated ICER, our findings suggest that although the addition of APR is cost-effective, FosAPR is not cost-effective.